11351 research outputs found
Sort by
Optimal harvesting in forestry: Steady-state analysis and climate change impact
No full textWe perform the steady-state analysis of a nonlinear partial differential equation model that describes the dynamics of a managed size-structured forest. The harvesting policy is to maximize the net benefits from timber production over an infinite planning horizon. The existence and uniqueness of the steady-state trajectories are analysed. Closed-form steady states are obtained in meaningful special cases and are used to estimate how climate change affects the optimal harvesting regime, diameter of cut trees, number of logged trees, and net benefits in the long run. © 2013 Natali Hritonenko
Physiological perspectives of reduced tillering and stunting in the tiller inhibition (tin) mutant of wheat
No full textThe number of tillers established in cereal crops far exceeds the number that end up being grain bearing at maturity. Improving the economy in tillering has been proposed to improve cereal yields in both favourable and unfavourable environments. The tiller inhibition mutant (tin) is potentially useful for breeding varieties with a greater economy of tillering. However, its tendency to stunting under long day and low temperatures has limited its use. Recently, the inhibition of tillering in tin has been linked to precocious development of solid basal internodes that compete for sucrose and possibly other resources with the growing tiller buds leading to their developmental arrest. Although the physiological basis of stunting in tin is unknown, both inhibition of tillering and stunting begin during the transition from vegetative to reproductive phase indicating a common physiological basis for both. In this review, we provide overall perspectives for the physiological basis of tiller inhibition and stunting in tin and suggest the direction of research in the future. Journal compilation © CSIRO 2013
Panther - November 2013 - Vol. XCIII, NO.10
Get PDFhttps://digitalcommons.pvamu.edu/pv-panther-newspapers2013/1000/thumbnail.jp
A Magazine For Alumni, Faculty and Supporters - February 2013
Get PDFhttps://digitalcommons.pvamu.edu/pv-magazine/1005/thumbnail.jp
Educational prediction markets: Construction project management case study
No full textEffective teaching of engineering concepts relies both on carefully designed lesson plans that meet specific learning outcomes and on classroom activities that students find engaging. Without student engagement, even the best designed plans will fail to meet their outcomes. In other words, students need to be actively involved in the learning process. The objective of this paper is to present a case study of applying a novel active learning method, specifically educational prediction markets (EPM), for teaching project management classes at a major research university. This method was investigated for its effectiveness in engaging students and promoting learning of probabilistic reasoning without explicit teaching. Student surveys, following the EPM implementation, revealed both advantages and disadvantages. The two key benefits reported by the students were: (1) providing better connections between the materials taught in the class and realities of construction projects; and (2) increasing overall interest and enthusiasm in learning about project risk management as a result of the gamelike nature of the process. The primary disadvantage was disengagement by a subset of students because of perceptions that fellow students were manipulating the market results. © 2013 American Society of Civil Engineers
Computational of optical micro-/nanoprism
No full textMany nanoscale materials have found wide applications in various scientific and engineering fields. Optical devices have also benefited from this trend. During the last decade, extensive research has been devoted to various metal nanoparticles. These structures manifest very interesting optical properties, which are strongly dependent on their shape and size. By artificially controlling their shapes and sizes, one can effectively tune the overall optical properties, a much desirable feature when building optical devices
Physically-Realizable Uniform Temperature Boundary Condition Specification on a Wall of an Enclosure: Part I – Problem Investigation
Get PDFDesigning an experimental apparatus requires considerable amount of planning. Despite proper planning, one can easily overlook a design such as the standard uniform temperature boundary condition applied to all or portion of a wall of an experimental apparatus. Although this boundary condition is mathematically simple and precise, achieving it physically may not be that simple. This paper addresses one such three-dimensional natural convection heat transfer apparatus that was designed to measure benchmark Nusselt numbers at various Rayleigh numbers with uniform temperatures specified at two walls of the enclosure. It was found that the effect of thermal spreading/constriction resistance on one wall where this uniform temperature condition was prescribed was significant, and as a result, the uniform temperature profile based on the initial design was not physically achieved. In support of this non-uniform temperature observation, this paper presents a thermal resistance model of a plate (which is a portion of this overall heat transfer apparatus) to explain the observed temperature non-uniformity. The results obtained from the current model are validated with measured data, and in terms of a temperature difference between two locations on the plate, the approximate analytical solution is well within the experimental error of 0.03K
An Exponential Matrix Method for Numerical Solutions of Hantavirus Infection Model
Get PDFIn this paper, a new matrix method based on exponential polynomials and collocation points is proposed to obtain approximate solutions of Hantavirus infection model corresponding to a class of systems of nonlinear ordinary differential equations. The method converts the model problem into a system of nonlinear algebraic equations by means of the matrix operations and the collocation points. The reliability and efficiency of the proposed scheme is demonstrated by the numerical applications and all numerical computations have been made by using a computer program written in Maple
An ε -Uniform Numerical Method for a System of Convection-Diffusion Equations with Discontinuous Convection Coefficients and Source Terms
Get PDFIn this paper, a parameter-uniform numerical method is suggested to solve a system of singularly perturbed convection-diffusion equations with discontinuous convection coefficients and source terms subject to the Dirichlet boundary condition. The second derivative of each equation is multiplied by a distinctly small parameter, which leads to an overlap and interacting interior layer. A numerical method based on a piecewise uniform Shishkin mesh is constructed. Numerical results are presented to support the theoretical results